Method and Apparatus for Enhanced Cleaning and Inspection

ABSTRACT

A cleaning and inspection system includes a cleaning chamber and retaining structure disposed within the cleaning chamber and configured to secure an article to be cleaned within the cleaning chamber. The cleaning and inspection system also includes a gas distributor disposed within the cleaning chamber and configured to distribute a turbulent flow of gas into the cleaning chamber that facilitates removal of foreign particles from a surface of the article. Further, the system includes a particle collection surface positioned to collect foreign particles removed from the surface of the article.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. In the course of IC evolution, functional density (i.e., thenumber of interconnected devices per chip area) has generally increasedwhile geometry size (i.e., the smallest component (or line) that can becreated using a fabrication process) has decreased. This scaling downprocess generally provides benefits by increasing production efficiencyand lowering associated costs. Such scaling down has also increased thecomplexity of processing and manufacturing ICs and, for these advancesto be realized, similar developments in IC manufacturing are needed.

For example, in semiconductor technologies, a plurality of photomasks(masks) are formed with predesigned IC patterns. The plurality of masksare used during lithography processes to transfer the predesigned ICpatterns to multiple semiconductor wafers. As such, photomask must besubstantially devoid of foreign particles during the lithographyprocess. Commonly, photomasks are transported between stations in asemiconductor fabrication facility inside of a transportation/storagepod. Some types of photomasks are protected by pellicles duringtransportation, however, other types of photomasks—such as masks usedfor EUV (extreme ultraviolet) lithography—may not be protectable bypellicles. Further, EUV photomasks may be more sensitive tocontamination because of smaller feature size. Thus, in some cases,foreign particles attached to the inside of a pod may transfer aphotomask during transportation. Accordingly, it may be desirable tothoroughly clean a photomask pod before it is used to transport aphotomask. However, it may be difficult to determine if a pod issubstantially free of foreign particles after a cleaning. Thus, althoughexisting systems and approaches have been satisfactory for theirintended purposes, they have not been entirely satisfactory in allrespects.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 is a simplified block diagram of an embodiment of an integratedcircuit (IC) manufacturing system and an associated IC manufacturingflow.

FIG. 2 illustrates an exploded perspective view of an example photomaskpod and a photomask stored in the pod.

FIG. 3 illustrates a system configured to remove foreign particles fromarticles such as photomask transportation and storage pods and todetermine the cleanliness of the articles after the removal according toaspects of the present disclosure.

FIG. 4 is a more detailed view of a portion of the system 200 of FIG. 3.

FIG. 5 illustrates a corner of the article of FIGS. 3 and 4 thatincludes a plurality of foreign particles attached thereto.

FIG. 6 illustrates a further embodiment of a cleaning chamber thatsimilar to the cleaning chamber in FIGS. 3 and 4.

FIG. 7 illustrates a high-level flowchart of a method of removingparticles from an article and determining the cleanliness of the articleaccording to various aspects of the present disclosure.

DETAILED DESCRIPTION

It is understood that the following disclosure provides many differentembodiments, or examples, for implementing different features of theinvention. Specific examples of components and arrangements aredescribed below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

FIG. 1 is a simplified block diagram of an embodiment of an integratedcircuit (IC) manufacturing system 100 and an IC manufacturing flowassociated with the IC manufacturing system. The IC manufacturing system100 includes a plurality of entities, such as a design house 120, a maskhouse 130, and an IC manufacturer 158 (i.e., a fab), that interact withone another in the design, development, and manufacturing cycles and/orservices related to manufacturing an integrated circuit (IC) device 162.The plurality of entities are connected by a communications network,which may be a single network or a variety of different networks, suchas an intranet and the Internet, and may include wired and/or wirelesscommunication channels. Each entity may interact with other entities andmay provide services to and/or receive services from the other entities.The design house 120, mask house 130, and IC manufacturer 150 may be asingle entity or separate entities.

The design house (or design team) 120 generates an IC design layout 122.The IC design layout 122 includes various geometrical patterns designedfor an IC product, based on a specification of the IC product to bemanufactured. The geometrical patterns correspond to patterns of metal,oxide, or semiconductor layers that make up the various components ofthe IC device 162 to be fabricated. The various layers combine to formvarious IC features. For example, a portion of the IC design layout 122includes various IC features, such as an active region, gate electrode,source and drain, metal lines or vias of an interlayer interconnection,and openings for bonding pads, to be formed in a semiconductor substrate(such as a silicon wafer) and various material layers disposed on thesemiconductor substrate. The design house 120 implements a proper designprocedure to form the IC design layout 122. The design procedure mayinclude logic design, physical design, and/or place and route. The ICdesign layout 122 is presented in one or more data files havinginformation of the geometrical patterns. For example, the IC designlayout 122 can be expressed in a GDSII file format (or DFII fileformat).

The mask house 130 uses the IC design layout 122 to manufacture one ormore masks to be used for fabricating the various layers of the ICproduct according to the IC design layout 122. The mask house 130performs mask data preparation 132, where the IC design layout 122 istranslated into a form that can be physically written by a mask writer.Data preparation 132 may include optical proximity correction (OPC) anda lithography process check (LPC) to compensate for image errors andsimulate mask fabrication. The mask house 130 also performs maskfabrication 144, where the design layout prepared by the mask datapreparation 132 is modified to comply with a particular mask writerand/or mask manufacturer and is then fabricated. In the presentembodiment, the mask data preparation 132 and mask fabrication 144 areillustrated as separate elements, however, the mask data preparation 132and mask fabrication 144 can be collectively referred to as mask datapreparation.

During mask fabrication 144, a mask or group of masks are fabricatedbased on the modified IC design layout. For example, an electron-beam(e-beam) or a mechanism of multiple e-beams is used to form a pattern ona mask (photomask or reticle) based on the modified IC design layout.The mask can be formed in various technologies. In one embodiment, themask is formed using binary technology. In the present embodiment, amask pattern includes opaque regions and transparent regions. Aradiation beam, such as an ultraviolet (UV) beam, used to expose theimage sensitive material layer (e.g., photoresist) coated on a wafer, isblocked by the opaque region and transmits through the transparentregions. In one example, a binary mask includes a transparent substrate(e.g., fused quartz) and an opaque material (e.g., chromium) coated inthe opaque regions of the mask. In another example, the mask is formedusing a phase shift technology. In the phase shift mask (PSM), variousfeatures in the pattern formed on the mask are configured to have properphase difference to enhance the resolution and imaging quality. Invarious examples, the phase shift mask can be attenuated PSM oralternating PSM as known in the art. In other embodiments, the photomaskmay be an EUV (extreme ultraviolet) photomask suitable for lithographyprocesses using light radiation having wavelengths in the range of about13.5 nm or less.

After a mask has been fabricated, the mask house performs a maskinspection 146 to determine if the fabricated mask includes any defects,such as full-height and non-full-height defects. If any defects aredetected, the mask may be cleaned or the IC design may be modifiedfurther depending on the types of defects detected.

It should be understood that the above description of the mask datapreparation 132 has been simplified for the purposes of clarity, anddata preparation may include additional features such as a logicoperation (LOP) to modify the IC design layout according tomanufacturing rules, a retarget process (RET) to modify the IC designlayout to compensate for limitations in lithographic processes used byIC manufacturer 150, and a mask rule check (MRC) to modify the IC designlayout to compensate for limitations during mask fabrication 144.Additionally, the processes applied to the IC design layout 122 duringmask fabrication 144 and mask inspection 146 may be executed in avariety of different orders and may include a variety of differentand/or additional steps.

After a photomask has been fabricated by the mask house 130, it may betransported to various locations, such as the IC manufacturer 158 (i.e.,fab). To prevent damage during transportation, photomasks are stored andtransported in transportation containers/carriers, such as a photomaskpod 148 shown in FIG. 1. In this regard, FIG. 2 illustrates an explodedperspective view of an example photomask pod 150 and a photomask 152stored in the pod. Specifically, the pod 150 may include a top coverportion 154 and a bottom cover portion 156. In one embodiment, the pod150 may have a dual pod design and include various other portions andfeatures, for instance, the pod may include an inner pod assembly with acover and base plate and an outer pod assembly that fits around theinner pod assembly. For the sake of clarity, these are not shown in FIG.2. In the illustrated embodiment, the pod 150 is designed to hold an EUVphotomask that is not protected by a pellicle. Thus, it is desirable forthe pod 150 to be entirely or substantially free of foreign particlesbefore the photomask 152 is transported inside of the pod so that thephotomask is not contaminated. In other embodiments, the pod may be someother type of storage and/or transportation receptacle that is moresuitable for use when it is free or substantially free of foreignparticles.

Referring back to FIG. 1, the IC manufacturer 158, such as asemiconductor foundry, uses the mask (or masks) fabricated by the maskhouse 130 to fabricate the IC device 162. The IC manufacturer 158 is aIC fabrication business that can include a myriad of manufacturingfacilities for the fabrication of a variety of different IC products.For example, there may be a manufacturing facility for the front endfabrication of a plurality of IC products (i.e., front-end-of-line(FEOL) fabrication), while a second manufacturing facility may providethe back end fabrication for the interconnection and packaging of the ICproducts (i.e., back-end-of-line (BEOL) fabrication), and a thirdmanufacturing facility may provide other services for the foundrybusiness. In the present embodiment, a semiconductor wafer 160 isfabricated using the mask (or masks) to form the IC device 162. Thesemiconductor wafer includes a silicon substrate or other propersubstrate having material layers formed thereon. Other proper substratematerials include another suitable elementary semiconductor, such asdiamond or germanium; a suitable compound semiconductor, such as siliconcarbide, indium arsenide, or indium phosphide; or a suitable alloysemiconductor, such as silicon germanium carbide, gallium arsenicphosphide, or gallium indium phosphide. The semiconductor wafer mayfurther include various doped regions, dielectric features, andmultilevel interconnects (formed at subsequent manufacturing steps). Themask may be used in a variety of processes. For example, the mask may beused in an ion implantation process to form various doped regions in thesemiconductor wafer, in an etching process to form various etchingregions in the semiconductor wafer, in a deposition process (e.g.,chemical vapor deposition (CVD) or physical vapor deposition (PVD)) toform a thin film in various regions on the semiconductor wafer, and/orother suitable processes.

FIG. 3 illustrates a system 200 configured to remove foreign particlesfrom articles photomask transportation and storage pods and to determinethe cleanliness of the articles after the removal according to aspectsof the present disclosure. In one embodiment, the system 200 is operableto remove particles sized in the range of about 10-35 nm. These sizeparticles are especially disruptive of lithography processes utilizingEUV photomasks. It is understood that although the present disclosureincluding FIGS. 3-7 is directed to removing particles from photomasktransportation pods, the methods and systems described below may beutilized to clean and determine the cleanliness of a wide variety ofarticles that may have foreign particles disposed thereon.

In more detail, the system 200 includes a cleaning chamber 202, apass-through chamber 204, and a particle collection chamber 204, wherethe pass-through chamber couples the cleaning chamber to the particlecollection chamber such that they are in fluid communication. Thecleaning chamber 202 may be sealed and pressurized so the pressurewithin the chamber may be controlled to suit the specific cleaningprocess employed. For instance, a vacuum may be formed in the cleaningchamber 202 to assist in the removal of all moisture from the articlebeing cleaned. Further, in one embodiment, a specific atmosphericpressure may be created within the chamber so as to most efficientlypropagate ultrasonic sounds toward an article being cleaned. Thecleaning chamber 202 includes retaining structures 208 that areconfigured to hold an article 210 to be cleaned within the cleaningchamber 202. The retaining structures 208 are adjustable so that theymay retain a wide variety of differently shaped and sized articles. Forexample, in the illustrated embodiment of FIG. 3, the article 210 is acover of a photomask transportation pod, such as the top cover portion154 of FIG. 2. Because the retaining structures are adjustable, aphotomask pod may be disassembled and each piece may be separatelycleaned within the chamber 202 even if they are different sizes andshapes. Further, the retaining structures 208 are rotatable relative tothe interior of the chamber 202. Accordingly, the article 210 may berotated during a cleaning process so that all surfaces may be exposedand also so that loose particles disposed on a surface of the article210 may fall away from the article during the rotation.

The system 200 further includes a gas distributor 212 disposed withinthe cleaning chamber 202. The gas distributor 202 is configured toinject gas molecules into the cleaning chamber 202 for various particleremoval techniques. A gas inlet 214 feeds gas from various sources intothe gas distributor 212 where it is dispersed into the cleaning chamber202. In one embodiment, the gas inlet 214 includes a control mechanismto control the amount and velocity of the gas entering the cleaningchamber 202. As will be discussed in greater detail below, the gasdistributor includes a plurality of distribution apertures through whichthe gas enters the chamber. In one embodiment, the plurality ofdistribution apertures may vary in size and shape. Depending on thecleaning process employed by the system 200, various different types ofgas may be distributed into the cleaning chamber 202. For example,nitrogen, argon, and oxygen are some examples of gases that may bedistributed into the cleaning chamber to remove particles from anarticle such as the article 210. In the illustrated embodiment, the gasdistributor is operable to disburse electrically charged gas molecules216 into the cleaning chamber 210 during a cleaning process. In oneembodiment, the distributor 212 includes a charging mechanism to chargethe gas molecules as they flow through the distributor. Such charged gasmolecules may be utilized to remove particles in various manners. Forexample, foreign particles may be attracted to and thus attached to thearticle 210 because the particles have an electrical charge, static orotherwise. Subjecting the charged foreign particles to charged gas mayneutralize the particles, weakening their attraction to the article 210.Further, the force of the gas 216 as projected out of the distributor212 may also forcibly remove any particles attached to the article 210.The manner in which the charged gas 216 may be utilized to removeforeign particles is discussed in greater detail in association withFIGS. 4 and 5.

The system 200 further includes a vibration generator 218 disposed inthe cleaning chamber 202. The vibration generator 218 is operable toimpart physical movement such as vibrations to the article 210, thusfacilitating the removal of foreign particles from the article'ssurface. In one embodiment, the vibration generator 218 may be utilizedin conjunction with the charged gas 216 to remove foreign particles fromthe cover. For example, the charged gas 216 may neutralize any chargedforeign particles thus lessening their attraction to the article 210. Ifthe neutralized particles do not immediately detach from the article210, the vibration generator 218 is operable to vibrate the article andshake loose the remaining particles. The vibration generator 218 mayutilize a variety of mechanisms to impart movement to the article to becleaned in the chamber 202. In one embodiment, the vibration generator218 directs ultrasonic waves at the cover 210. Such ultrasonic wavesimpart vibrations into the cover 210, thus simulating the vibrationscaused by transportation. Ideally, any foreign particles that wouldshake loose onto a photomask during transportation will shake looseduring the cleaning process instead. To facilitate the propagation ofultrasonic waves through the cleaning chamber 202, the chamber 210 maybe pressurized to a specific pressure to most efficiently effect thecleaning process. In one embodiment, the vibration generator 218 mayvary the intensity, power, and wavelength of the ultrasonic wavesdirected at the article 210. In another embodiment, the vibrationgenerator 218 directs pulsed laser energy at the article 210 to impartshock waves in the article. For instance, the vibration generator 218may direct a laser pulse of high power (e.g., over 10⁹ W/cm²) and shortduration (e.g. a nanosecond) at the article 210 and as the laser energyimpacts the surface of the article a shock wave is generated. This shockwave may loosen or entirely detach foreign particles attached to thearticle 210. Because laser energy is focused on a particular location,the vibration generator 218 may be configured to scan the pulsed laserenergy across the surface of the article 210. The power and duration ofthe laser emanating from the vibration generator may be tuned based onthe type of material out of which the article is constructed. Inalternative embodiments, the vibration generator 218 may utilizedifferent techniques to generate vibrations or other movement in thearticle 210 such that foreign particles attached thereto are loosened ordetached.

In the illustrated embodiment, the system 200 further includes anultraviolet (UV) light source 219 disposed in the cleaning chamber 202.The UV light source 219 is configured to be used in conjunction withoxygen (O₂) gas injected into the cleaning chamber 219 by the gasdistributor 212 to create ozone gas (O₃). Specifically, ozone gas formedin the cleaning chamber 202 by oxygen absorbing UV light is utilized todecompose any organic foreign particles attached to the article 210. Theozone gas may not remove organic particles from the article 210 but itmay shrink them, making them easier to remove by other methods such asvibrations. Further, the system 200 includes a carbon dioxide (CO₂) snowjet 220 to aid in the removal of foreign particles attached to thearticle 210. Specifically, the snow jet 220 ejects a stream ofcrystallized carbon dioxide particles that impacts the surface of thearticle 210 and dislodges any foreign particles attached thereto throughmomentum transfer.

It is understood that the particle removal systems described aboveincluding the gas distributor 212, the vibration generator 218, the UVlight source 219, and the carbon dioxide (CO₂) snow jet 220 and themethods of cleaning associated with each are simply examples of cleaningmechanisms that may be employed within the cleaning chamber 202. Variousembodiments of the system 200 may include different subsets of thecleaning mechanisms and they may be used alone or in combination toeffectuate particle removal from the article 210. Further, additionaland/or different cleaning systems and methods may be employed to cleanarticles within the cleaning chamber 202 without departing from thescope of the present disclosure. For instance, the retaining structures208 may be operable to physically vibrate an article held between themto dislodge particles attached to the article.

While subjecting the article 210 to the various cleaning mechanismdescribed above, foreign particles 221 will ideally detach from thearticle. The system 200 is configured such that the detached particles221 fall from the article 210 and flow through the pass-through chamber204 and into the particle collection chamber 206. The particlecollection chamber 206 includes a particle collection surface 222 thatis disposed beneath the pass-through chamber 204. In the illustratedembodiment, the pass-through chamber 204 is configured to direct thedetached particles 221 onto the particle collection surface 222. In thatregard, the particle collection surface 222 has a width greater or equalto the pass-through chamber 204 so that all particles moving through thepass-through chamber 204 are deposited on the surface 222. Further, theparticle collection chamber 206 includes a gas outlet valve 224 thatexpels gas out of the system 200. The gas outlet value 224 is disposedwithin the particle collection chamber such that gas output by the gasdistributor 212 flows past the article 210, through the pass-throughchamber 204, and in the direction of the particle collection surface222. Thus, as gas flows through the system 200, it carries any detachedforeign particles 221 away from the article 210 and deposits them on theparticle collection surface 222. In one embodiment, the gas outlet valueis coupled to a pumping system (not illustrated) that creates a pressuredifferential in the particle collection chamber 206 such that detachedparticles 221 flow more efficiently toward the particle collectionsurface 222.

In one embodiment, the particle collection surface 222 is a siliconwafer, but in alternative embodiments, the surface 222 may be any othersurface operable to collect foreign particles deposited thereon. In someembodiments, the particle collection surface 222 includes a coatingconfigured to secure particles to the surface once they are deposited.In another embodiment, an electric charge is applied to the particlecollection surface 222 to attract foreign particles that detached fromthe article 210.

After a cleaning process has been completed and foreign particles havedetached from the article 210 and been deposited onto the particlecollection surface 222, the collection surface is removed from theparticle collection chamber 206 and inspected. If no foreign particlesare detected on the collection surface, it is likely that the article210 is free or substantially free of foreign particles. If particles aredetected on the collection surface, additional particles may remainattached to the article, and thus another round of cleaning may bedesired. In one embodiment, the collection surface 222 may be inspectedwith semiconductor wafer and photomask inspections tools such as opticalinspection tools and electron-beam (e-beam) inspection tools todetermine if the collection surface has any foreign particles depositedthereon. Because an e-beam inspection tool (i.e., scanning electronmicroscope) is capable of higher resolution imaging than an opticalinspection tool, it may be better suited for inspecting for particles onthe collection surface that are below about 20 nm in size. In otherembodiments, the collection surface 222 may be inspected with differentand/or additional inspection tools such as a scanning probe microscopesystem, a laser microscope system, a transmission electron microscopesystem, a focus ion beam microscope system, or other suitable imagingtools. In one embodiment, the particle collection surface 222 isinspected before it is inserted into the system 200 so that anyparticles attached to the collection surface prior to the cleaningprocess are not counted during the after-cleaning inspection. A methodof removing foreign particles from an article and determining thecleanliness of the article will be discussed in association with FIG. 7.

It is understood that the illustrated embodiment of system 200 in FIG. 3is simply an example and the system may be altered without departingfrom the scope of the present disclosure. For example, one embodiment ofsystem 200 may exclude the pass-through chamber 204 and another mayinclude only the cleaning chamber 202, where the particle collectionsurface 222 is disposed within the cleaning chamber 202.

FIG. 4 illustrates a portion of the system 200 of FIG. 3. Specifically,FIG. 4 is a more detailed view of the cleaning chamber 202 in which thearticle 210 is retained by the retaining structures 208. As mentionedabove and shown in FIG. 4, the retaining structures 208 are rotatablesuch that an article held between them may be turned for more effectivecleaning. Further, FIG. 4 includes a more detailed view of the gasdistributor 212. The gas distributor 212 is configured to eject aturbulent flow—rather than a laminar flow—of gas molecules into thecleaning chamber 202. In this regard, the gas distributor includes aplurality of distribution apertures 250 through which the gas injectedinto the cleaning chamber 202 passes. The size and placement of theapertures 250 on the gas distributor 212 affects the flow of gas out ofthe distributor, and, as shown in the illustrated embodiment, causes theflow of gas into the chamber 202 to be turbulent. In the exampleembodiment of FIG. 4, the apertures 250 in the center portion of the gasdistributor 212 are larger than the apertures in the edges portions ofthe distributor. The uneven distribution of the gas molecules 216creates turbulence, which increases the effectiveness of the gas inremoving particles from the article 210. In more detail, while a laminarflow of gas molecules may contact all flat surfaces of the article 210in the cleaning chamber 202, it may not reach all corners and opening ofthe article. However, the turbulent flow of gas molecules 216 maycontact all or a substantial portion of the surface area of the article216, including any corners and openings. In this regard, FIG. 5illustrates a corner 252 of the article 210 that includes a plurality offoreign particles 254 attached thereto. In the illustrated example, theturbulent flow of gas molecules 216 has flowed into the corner 252 andhas formed an eddy 256 within the corner. The eddy 256 makes it morelikely that the gas molecules 216 will contact the foreign particles 254in the corner 252 and either physically dislodge them or neutralizetheir charge so they detach more easily during other cleaningprocedures. It is understood that in alternative embodiments, theplurality of apertures in the gas distributor 212 may be sizeddifferently and positioned in an alternate manner than as shown in theillustrated embodiment of FIG. 4. Further, the gas distributor 212 maycreate a turbulent flow of gas molecules in the cleaning chamber 202 inan alternate manner in alternative embodiments.

Referring now to FIG. 6, illustrated is a further embodiment of acleaning chamber 300 that similar to the cleaning chamber 202 in FIGS. 3and 4. For the sake of convenience, features in FIG. 6 similar tofeatures in FIGS. 3-4 have been labeled with similar reference numeralsbut this labeling scheme is not intended to limit the illustratedembodiments of FIGS. 3-6. The cleaning chamber 300 may be a portion of asystem similar to system 200 of FIG. 3 or it may be a portion of asystem configured differently than system 200.

In the illustrated embodiment of FIG. 6, the article 210 is securedinside of the cleaning chamber 300 by the rotatable retaining structures208. As discussed above, the article 210 may be any article that hasunwanted foreign particles attaches thereto. In the illustratedembodiment, the article 210 is a cover of a photomask transportationpod, but, in other embodiments, the article may be other items that arerequired to be substantially free of foreign particles. The cleaningchamber 300 differs from the cleaning chamber 202 of FIGS. 3 and 4 inthat it includes a plurality of gas distributors. The gas distributor212 is disposed at a top portion of the chamber 300 and two additionalgas distributors 302 and 304 are disposed at opposing side portions ofthe chamber. The gas distributor 302 is fed by a gas inlet valve 306 andthe gas distributor 304 is fed by a gas inlet valve 308. Like the gasdistributor 212, the gas distributor 302 includes a plurality ofdistribution apertures 310. The apertures 310 vary in size and thus eachinjects a different amount of gas into the chamber 300. In theillustrated embodiment of FIG. 6, the apertures 310 decrease in sizealong the length of the gas distributor 302, with the smallest aperturesbeing most near the article 210. This variation of aperture size createsa turbulent flow of gas molecules 312. Further, the flow of gas out ofthe distributor 302 intermixes with the flow of gas out of thedistributors 212 and 304 creating additional turbulence in the chamber300. As mentioned above, this turbulence allows the gas molecules 312 tointeract with foreign particle attached disposed in corners and openingsin the article 210. It is understood that the plurality of apertures maybe sized and arranged in alternate manners in alternative embodiments tocreate different types of gas flows within the chamber 300. For example,in one embodiment, the plurality of apertures in the gas distributor 304may be arranged differently than the plurality of apertures 310 in thegas distributor 302.

Referring now to FIG. 7, illustrated is a high-level flowchart of amethod 350 of removing particles from an article and determining thecleanliness of the article according to various aspects of the presentdisclosure. In one embodiment, the method 350 may be carried out, forexample, with system 200 of FIG. 2.

The method 350 begins at block 352 where the article 210 is securedwithin the cleaning chamber 202 using the retaining structures 208. Theretaining structures may be adjusted based on the size and shape of thearticle being cleaned. The method 350 next proceeds to block 354 wherethe particle collection surface 222 is inspected for pre-existingparticles. In one embodiment, if pre-existing particles are detected,the collection surface is cleaned, but, in other embodiments, thepre-existing particles are simply noted and subtracted from anyparticles detected after the cleaning process. After the particlecollection surface 222 is inspected, it is inserted into the particlecollection chamber 206 prior to a cleaning process. Next, the method 350proceeds to block 356 where the article 210 is subjected to a cleaningprocess in the cleaning chamber 202 that removes any foreign particlesattached to the article's surface. As discussed above, may differentcleaning processes may be employed for particle removal. For example, aturbulent flow of charged gas molecules 216 may be distributed into thecleaning chamber 202 to dislodge and/or neutralize particles attached tothe article 210. Further, the vibration generator 218 may be utilized toimpart vibrations in the article 210 and shake loose previouslyneutralized particles. Further, additional and/or different cleaningprocesses may be employed to remove foreign particles from the article210 such as the use of ozone to decompose organic particles and/or a jetof carbon dioxide snow.

Next, in block 358, foreign particles detached from the article 210 aredeposited on the particle collection surface 222 as the cleaning processis being performed. The detached particles may be carried to theparticle collection surface by the flow of gas from the cleaning chamber202 to the particle collection chamber 206. After the cleaning processis complete, the method 350 proceeds to block 360 where the particlecollection surface 222 is inspected to determine the cleanliness of thearticle 210. Specifically, the particle collection surface 222 isinspected to determine if any particles were detached from the article210 and deposited on the particle collection surface. In decision block362, it is determined whether there are foreign particles on theparticle collection surface. If foreign particles are detected on theparticle collection surface, the method 350 returns to block 356 wherethe article is cleaned again. If at the decision block 362 it isdetermine that no particles were deposited on the particle collectionsurface during the cleaning, the method 350 proceeds to block 366 andthe article is deemed free or substantially free of foreign particlesand may be utilized for cleanliness-sensitive tasks. For example, if thearticle is a portion of a photomask transportation pod, it may now becombined with other clean portions of the photomask pod and the pod maybe used to store or transport photomasks. The cleaning and inspectingcycle of method 350 may be repeated until no particles are detected onthe particle collection surface and the article may be deemed clean.

It is understood that method 350 of cleaning and determining thecleanliness of an article is simply an example embodiment, and inalternative embodiments, additional and/or different steps may beincluded in the method. For example, in one embodiment, in the decisionblock 362, the number of particles detected on the particle collectionsurface may be compared against a cleanliness threshold and if thenumber of particles detected is below the threshold, the article will bedeemed clean.

Further, portions of the method 350 cleaning and determining thecleanliness of an article of the illustrated embodiment may be designedto be executed on any computing architecture. For example, portions ofthe method 350 may be executed on a single computer, local areanetworks, client-server networks, wide area networks, internets,hand-held and other portable and wireless devices and networks. Sucharchitecture can take the form of an entirely hardware embodiment, anentirely software embodiment, or an embodiment containing both hardwareand software elements. Hardware generally includes at leastprocessor-capable platforms, such as client-machines (also known aspersonal computers or servers), and hand-held processing devices (suchas smart phones, personal digital assistants (PDAs), or personalcomputing devices (PCDs), for example. Hardware can include any physicaldevice that is capable of storing machine-readable instructions, such asmemory or other data storage devices. Other forms of hardware includehardware sub-systems, including transfer devices such as modems, modemcards, ports, and port cards, for example. Software generally includesany machine code stored in any memory medium, such as RAM or ROM, andmachine code stored on other devices (such as floppy disks, flashmemory, or a CDROM, for example). Software can include source or objectcode, for example. In addition, software encompasses any set ofinstructions capable of being executed in a client machine or server.

Furthermore, embodiments of the present disclosure can take the form ofa computer program product accessible from a tangible computer-usable orcomputer-readable medium providing program code for use by or inconnection with a computer or any instruction execution system. For thepurposes of this description, a tangible computer-usable orcomputer-readable medium can be any apparatus that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The medium can be an electronic, magnetic, optical, electromagnetic,infrared, a semiconductor system (or apparatus or device), or apropagation medium.

Data structures are defined organizations of data that may enable anembodiment of the present disclosure. For example, a data structure mayprovide an organization of data, or an organization of executable code.Data signals could be carried across transmission mediums and store andtransport various data structures, and, thus, may be used to transportan embodiment of the present disclosure.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

In one exemplary aspect, the present disclosure is directed to acleaning and inspection system. The cleaning and inspection systemincludes a cleaning chamber and retaining structure disposed within thecleaning chamber and configured to secure an article to be cleanedwithin the cleaning chamber. The cleaning and inspection system alsoincludes a gas distributor disposed within the cleaning chamber andconfigured to distribute a turbulent flow of gas into the cleaningchamber that facilitates removal of foreign particles from a surface ofthe article. Further, the system includes a particle collection surfacepositioned to collect foreign particles removed from the surface of thearticle.

In another exemplary aspect, the present disclosure is directed to amethod of cleaning and inspecting an article. The method includessecuring the article within a cleaning chamber using retaining structureand distributing a turbulent flow of gas into the cleaning chamber tofacilitate the removal of any foreign particles attached to a surface ofthe article. The method also includes collecting any foreign particlesremoved from the surface of the article on a particle collection surfaceand inspecting the particle collection surface to determine the presenceof any foreign particles removed from the surface of the article.

In yet another exemplary aspect, the present disclosure is directed to acleaning and inspection system. The cleaning and inspection systemincludes a cleaning chamber, a pass-through chamber coupled to thecleaning chamber, and a particle collection chamber coupled to thepass-through chamber and in fluid communication with the cleaningchamber via the pass-through chamber. The system also includes retainingstructure disposed within the cleaning chamber and configured to securean article to be cleaned within the cleaning chamber and a gasdistributor disposed within the cleaning chamber and configured todistribute a turbulent flow of electrically charged gas into thecleaning chamber that neutralizes any electrically charged foreignparticles attached to a surface of the article. Further, the systemincludes a vibration generator disposed within the cleaning chamber andconfigured to impart movement to the article such that any foreignparticles neutralized by the electrically charged gas are detached fromthe surface of the article and a particle collection surface disposedwithin the particle collection chamber and positioned with respect tothe pass-through chamber so as to collect foreign particles removed fromthe surface of the article.

What is claimed is:
 1. A cleaning and inspection system, comprising: acleaning chamber; retaining structure disposed within the cleaningchamber and configured to secure an article to be cleaned within thecleaning chamber; a gas distributor disposed within the cleaning chamberand configured to distribute a turbulent flow of gas into the cleaningchamber that facilitates removal of foreign particles from a surface ofthe article; and a particle collection surface positioned to collectforeign particles removed from the surface of the article.
 2. Thecleaning and inspection system of claim 1, wherein the gas distributorincludes a plurality of distribution apertures sized to create theturbulent flow of gas.
 3. The cleaning and inspection system of claim 2,wherein distribution apertures in the plurality of distributionapertures are larger in a center portion of the gas distributor than inopposing edge portions of the gas distributor.
 4. The cleaning andinspection system of claim 2, wherein distribution apertures in theplurality of distribution apertures decrease in size from one edgeportion of the gas distributor to an opposing edge portion of the gasdistributor.
 5. The cleaning and inspection system of claim 1, whereinthe gas distributor is operable to electrically charge gas moleculeswithin the turbulent flow of gas, the electrically charged gas moleculesneutralizing electrically charged foreign particles attached to thesurface of the article.
 6. The cleaning and inspection system of claim1, further including a vibration generator disposed in the cleaningchamber and configured to impart movement in the article to facilitatethe removal of the foreign particles from the surface of the article. 7.The cleaning and inspection system of claim 6, wherein the vibrationgenerator is configured to direct ultrasonic waves at the article toimpart vibrations in the article.
 8. The cleaning and inspection systemof claim 6, wherein the vibration generator is configured to directpulsed laser energy at the article to impart shock waves in the article.9. The cleaning and inspection system of claim 1, wherein the gasdistributor is one of a plurality of gas distributors disposed in thecleaning chamber and wherein each is configured to distribute aturbulent flow of gas into the cleaning chamber.
 10. The cleaning andinspection system of claim 1, wherein the particle collection surface isa silicon wafer.
 11. The cleaning and inspection system of claim 1,further including an ultraviolet light source disposed within thecleaning chamber and configured to convert oxygen in the cleaningchamber into ozone gas to facilitate decomposition of organic particlesattached to the surface of the article.
 12. A method of cleaning andinspecting an article, comprising: securing the article within acleaning chamber using retaining structure; distributing a turbulentflow of gas into the cleaning chamber to facilitate removal of anyforeign particles attached to a surface of the article; collecting anyforeign particles removed from the surface of the article on a particlecollection surface; and inspecting the particle collection surface todetermine a presence of any foreign particles removed from the surfaceof the article.
 13. The method of claim 12, wherein the collectingincludes directing any foreign particles removed from the surface of thearticle toward the particle collection surface.
 14. The method of claim12, further including inspecting, prior to the collecting, the particlecollection surface to determine a presence of any pre-existingparticles.
 15. The method of claim 12, wherein the particle collectionsurface is a silicon wafer; and wherein the inspecting includesinspecting the wafer with a semiconductor wafer inspection tool.
 16. Themethod of claim 12, wherein distributing includes distributing the gasinto the cleaning chamber through a plurality of differently-sizeddistribution apertures, the plurality of differently-sized distributionapertures creating the turbulent flow of gas.
 17. The method of claim12, wherein distributing includes distributing charged gas moleculesinto the cleaning chamber to electrically neutralize any charged foreignparticles attached to the surface of the article.
 18. The method ofclaim 12, further including imparting physical movement in the articlewith a vibration generator disposed in the cleaning chamber tofacilitate the removal of any foreign particles attached to the surfaceof the article.
 19. A cleaning and inspection system, comprising: acleaning chamber; a pass-through chamber coupled to the cleaningchamber; a particle collection chamber coupled to the pass-throughchamber and in fluid communication with the cleaning chamber via thepass-through chamber; retaining structure disposed within the cleaningchamber and configured to secure an article to be cleaned within thecleaning chamber; a gas distributor disposed within the cleaning chamberand configured to distribute a turbulent flow of electrically chargedgas into the cleaning chamber that neutralizes any electrically chargedforeign particles attached to a surface of the article; a vibrationgenerator disposed within the cleaning chamber and configured to impartmovement to the article such that any foreign particles neutralized bythe electrically charged gas are detached from the surface of thearticle; and a particle collection surface disposed within the particlecollection chamber and positioned with respect to the pass-throughchamber so as to collect foreign particles removed from the surface ofthe article.
 20. The cleaning and inspection system of claim 19, whereinthe gas distributor includes a plurality of distribution apertures sizedto create the turbulent flow of gas.